printPerson(String name,{var age,dynamic gender}){
  print('name=$name,age=$age,gender=$gender');
}

printPerson2(String name,[var age=16,dynamic gender]){
  print('name=$name,age=$age,gender=$gender');
}

void main(){
  printPerson('Tom');
  printPerson('Alice',age:17,gender:'female');
  printPerson2('Judy');
  printPerson2('Bob',19,'male');
}
